Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, MA 02111, USA.
Am J Clin Nutr. 2010 May;91(5):1468S-1473S. doi: 10.3945/ajcn.2010.28674G. Epub 2010 Mar 3.
Recent progress in the measurement of the bioconversion of dietary provitamin A carotenoids to vitamin A is reviewed in this article. Methods to assess the bioavailability and bioconversion of provitamin A carotenoids have advanced significantly in the past 10 y, specifically through the use of stable isotope methodology, which includes the use of labeled plant foods. The effects of the food matrix on the bioconversion of provitamin A carotenoids to vitamin A, dietary fat effects, and the effect of genotype on the absorption and metabolism of beta-carotene have been reported recently. A summary of the major human studies that determined conversion factors for dietary beta-carotene to retinol is presented here, and these data show that the conversion efficiency of dietary beta-carotene to retinol is in the range of 3.6-28:1 by weight. There is a wide variation in conversion factors reported not only between different studies but also between individuals in a particular study. These findings show that the vitamin A value of individual plant foods rich in provitamin A carotenoids may vary significantly and need further investigation.
本文综述了近年来膳食维生素原 A 类胡萝卜素向维生素 A 生物转化的测定方法的研究进展。在过去的 10 年中，评估维生素原 A 类胡萝卜素生物可利用性和生物转化的方法取得了显著进展，特别是通过使用稳定同位素方法，包括使用标记的植物性食物。最近报道了食物基质对维生素原 A 类胡萝卜素向维生素 A 的生物转化、膳食脂肪效应以及基因型对β-胡萝卜素吸收和代谢的影响。本文总结了确定膳食β-胡萝卜素向视黄醇转化率的主要人体研究，这些数据表明，膳食β-胡萝卜素向视黄醇的转化率按重量计在 3.6-28:1 之间。不仅不同研究之间，而且在特定研究中的个体之间，转化率因子的报道差异很大。这些发现表明，富含维生素原 A 类胡萝卜素的个别植物性食物的维生素 A 值可能有很大差异，需要进一步研究。
